fix: centralize draft preview finalization

docs/.generated/plugin-sdk-api-baseline.sha256

@@ -1,2 +1,2 @@
-cfeee4630cb43ffc4d702f207d28d35962c6458aa8fd2b1671c35e0be158bb35  plugin-sdk-api-baseline.json
-af4fbf19861c6ec000b41ac5a3ded597700e45bb15f8b1d74bb2d1f550bd09b6  plugin-sdk-api-baseline.jsonl
+3a2cde4b15041b5456420b2052b572f9968a93690814d2cf924382fd2f54d1d3  plugin-sdk-api-baseline.json
+38cd9086be93fc9531a8036812c197118c7830d52d40424be08dc9c6d51092e2  plugin-sdk-api-baseline.jsonl

docs/channels/discord.md

@@ -593,6 +593,7 @@ Default slash command settings:
     - `channels.discord.streamMode` is a legacy alias and is auto-migrated.
     - `partial` edits a single preview message as tokens arrive.
     - `block` emits draft-sized chunks (use `draftChunk` to tune size and breakpoints).
+    - Media, error, and explicit-reply finals cancel pending preview edits without flushing a temporary draft before normal delivery.
     - `streaming.preview.toolProgress` controls whether tool/progress updates reuse the same draft preview message (default: `true`). Set `false` to keep separate tool/progress messages.
 
     Example:

docs/channels/mattermost.md

@@ -246,7 +246,7 @@ Notes:
 
 ## Preview streaming
 
-Mattermost streams thinking, tool activity, and partial reply text into a single **draft preview post** that finalizes in place when the final answer is safe to send. The preview updates on the same post id instead of spamming the channel with per-chunk messages.
+Mattermost streams thinking, tool activity, and partial reply text into a single **draft preview post** that finalizes in place when the final answer is safe to send. The preview updates on the same post id instead of spamming the channel with per-chunk messages. Media/error finals cancel pending preview edits and use normal delivery instead of flushing a throwaway preview post.
 
 Enable via `channels.mattermost.streaming`:
 

docs/channels/slack.md

@@ -742,6 +742,7 @@ Notes:
 - Channel and group-chat roots can still use the normal draft preview when native streaming is unavailable.
 - Top-level Slack DMs stay off-thread by default, so they do not show the thread-style preview; use thread replies or `typingReaction` if you want visible progress there.
 - Media and non-text payloads fall back to normal delivery.
+- Media/error finals cancel pending preview edits without flushing a temporary draft; eligible text/block finals flush only when they can edit the preview in place.
 - If streaming fails mid-reply, OpenClaw falls back to normal delivery for remaining payloads.
 
 Use draft preview instead of Slack native text streaming:

docs/concepts/streaming.md

@@ -149,17 +149,25 @@ Discord:
 - Uses send + edit preview messages.
 - `block` mode uses draft chunking (`draftChunk`).
 - Preview streaming is skipped when Discord block streaming is explicitly enabled.
+- Final media, error, and explicit-reply payloads cancel pending previews without flushing a new draft, then use normal delivery.
 
 Slack:
 
 - `partial` can use Slack native streaming (`chat.startStream`/`append`/`stop`) when available.
 - `block` uses append-style draft previews.
 - `progress` uses status preview text, then final answer.
+- Final media/error payloads and progress finals do not create throwaway draft messages; only text/block finals that can edit the preview flush pending draft text.
 
 Mattermost:
 
 - Streams thinking, tool activity, and partial reply text into a single draft preview post that finalizes in place when the final answer is safe to send.
 - Falls back to sending a fresh final post if the preview post was deleted or is otherwise unavailable at finalize time.
+- Final media/error payloads cancel pending preview updates before normal delivery instead of flushing a temporary preview post.
+
+Matrix:
+
+- Draft previews finalize in place when the final text can reuse the preview event.
+- Media-only, error, and reply-target-mismatch finals cancel pending preview updates before normal delivery; an already-visible stale preview is redacted.
 
 ### Tool-progress preview updates
 

docs/plugins/sdk-migration.md

@@ -202,7 +202,7 @@ Current bundled provider examples:
   | `plugin-sdk/channel-config-schema` | Config schema builders | Channel config schema types |
   | `plugin-sdk/telegram-command-config` | Telegram command config helpers | Command-name normalization, description trimming, duplicate/conflict validation |
   | `plugin-sdk/channel-policy` | Group/DM policy resolution | `resolveChannelGroupRequireMention` |
-  | `plugin-sdk/channel-lifecycle` | Account status tracking | `createAccountStatusSink` |
+  | `plugin-sdk/channel-lifecycle` | Account status and draft stream lifecycle helpers | `createAccountStatusSink`, draft preview finalization helpers |
   | `plugin-sdk/inbound-envelope` | Inbound envelope helpers | Shared route + envelope builder helpers |
   | `plugin-sdk/inbound-reply-dispatch` | Inbound reply helpers | Shared record-and-dispatch helpers |
   | `plugin-sdk/messaging-targets` | Messaging target parsing | Target parsing/matching helpers |

docs/plugins/sdk-overview.md

@@ -90,7 +90,7 @@ explicitly promotes one as public.
     | `plugin-sdk/telegram-command-config` | Telegram custom-command normalization/validation helpers with bundled-contract fallback |
     | `plugin-sdk/command-gating` | Narrow command authorization gate helpers |
     | `plugin-sdk/channel-policy` | `resolveChannelGroupRequireMention` |
-    | `plugin-sdk/channel-lifecycle` | `createAccountStatusSink` |
+    | `plugin-sdk/channel-lifecycle` | `createAccountStatusSink`, draft stream lifecycle/finalization helpers |
     | `plugin-sdk/inbound-envelope` | Shared inbound route + envelope builder helpers |
     | `plugin-sdk/inbound-reply-dispatch` | Shared inbound record-and-dispatch helpers |
     | `plugin-sdk/messaging-targets` | Target parsing/matching helpers |